Albert Barnes Commentary 1 John 2:11

"But he that hateth his brother is in the darkness, and walketh in the darkness, and knoweth not whither he goeth, because the darkness hath blinded his eyes." — 1 John 2:11 (ASV)

But he that hateth his brother. The word used here would, in this connection, include both the mere absence of love and positive hatred. It is intended to include the whole state of mind where there is no love for the brethren.

Is in darkness. (1 John 2:9).

And walketh in darkness. He is like one who walks in the dark and who sees no object distinctly. See Barnes on John 12:35.

And knoweth not whither he goeth. Like one in the dark. He wanders about, not knowing what direction he should take or where the course he is on will lead.

The general meaning is that he is ignorant of the whole nature of religion; or, in other words, love for the brethren is a central virtue in religion, and when a man does not have that, his mind is entirely clouded on the whole subject, and he shows that he knows nothing of its nature. There is no virtue that is intended to be more prominent in Christianity, and there is none that will cast its influence further over a man's life.